<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .green {
            color: greenyellow;
        }
    </style>
</head>

<body>
    <ul class="ul">
        <li>1111</li>
        <li>2222</li>
        <li>3333</li>
        <li class="p4">4444</li>
    </ul>
</body>
<script src="./demo3.js"></script>
<script>
    // let ret = $('li').addClass('green');
    // console.log('ret',ret);
    $('li').addClass('green').eq(1).setText('hahahah')
    $('.p4').setText('你好')
    $('ul').find('li').eq(2).setText('iowejkljhigdf');
    console.log('$',$);
</script>

</html>